190 



OSTEOLOGY. 



bone and the union of the latter with the maxilla. Just above this the opening of tin 

 pterygo-palatine canal, which leads from the pterygo-palatine fossa to the inferior surfaci 

 of the hard palate, is visible; whilst inferiorly a small portion of the lower part of thi 



pterygoid fossa is cut through 

 Within the choanse the middl< 

 and inferior conchae are seen 

 the inferior border of the forme: 

 corresponds to the level of th< 

 superior border of the zygomatii 

 arch, whilst the attached edge of thi 

 latter to the perpendicular part o 

 the palate lies in the same horizonta 

 plane as the inferior margins of tha 

 arch. Note also that the media 

 pterygoid laminae lie considerably 

 within the lines of the medial sur 

 faces of the alveolar border, am 

 reach some little distance below thi 

 level of the hard palate. 



The next section (Fig. 178 

 passes through the maudibular fossi 

 just behind the tuberculum articu 

 lare; superiorly, it cuts the vaul 

 half an inch behind the bregma. Thi 

 middle cranial fossa is shown ij 

 section, the floor of which descend 

 as low as the level of the inferio 

 surface of the body of the sphenoid 

 corresponding laterally to a hori 

 zontal plane passing through thi 

 superior edge of the posterior roo 

 of the zygoma. The body of thi 

 sphenoid rises a finger's breadtl 

 above this in the median plane ; thi 

 cavity within it is exposed, whils 

 on either side and below is seei 

 the groove for the internal carotk 

 artery, leading upwards from th< 

 medial part of the foramen lacerum 

 which is here divided. To thi 

 lateral side of the groove is seei 



28 i i ' ' Z6 the prominent edge of the lingula 



immediately below which is thi 

 FIG. 178. FRONTAL SECTION OF THE SKULL PASSING THROUGH THE noqtpri or a>rtnrP of thp ntewmnit 

 MANDIBULAR FOSSA JUST BEHIND THE TUBERCULUM ARTICULARE. P oste 7 ri o r apertur 



canal, the inferior edge of which ii 



15. 



in part concealed by the 

 tubercle. Immediately lateral tc 

 the foramen lacerum the foramen 



1. Crista galli of ethmoid. 



2. Posterior cliuoid process. 



3. Optic foramen. 



4. Anterior cliuoid process. 



5. Orbital part of frontal. 



6. Small wing of sphenoid. 



7. Suture between squamous pterygoid canal. , 



part of the temporal, and 19. Postero - lateral margin of Dna g e ( 



parietal bones. lateral pterygoid lamina. Overlie the root of the lateral ptery 



20. Groove for carotid artery. 



21. Pterygoid fossa. 



22. Scaphoid fossa. 



23. Hamulus of medial ptery 



goid lamina. 



24. Inferior concha. 



of sphenoid in 

 of spine. 



16. Foramen ovale. 



17. Lingula. 



18. Anterior margin of foramen ovale is seen separated from the 



lacerum and opening of sur f ace O f the section by a narrow 



nrawnrmH raiial v 



Here it is seen tc 



8. Superior orbital fissure. 



9. Cerebral surface of great 



wing of sphenoid. 



10. Foramen rotundum. 



1 1 . Squamous part of temporal. 



12. Posterior root of zygomatic 



process. 



13. Tuberculum articulare. 



14. Maudibular fossa. 



26' 



goid lamina. The section passes 

 just in front of the foramen spin- 

 osum, and here is visible the stoul 

 suture between the great wing oi 

 the sphenoid and the squamous parl 

 of the temporal bone. The man- 



27. Openingofsphenoidalsinus. dibular fossa of the temporal boj 



28. Dorsum sellae. is cut on either side, and in i 



deepest part is separated from tiu 



middle cranial fossa by but a thin lamina of bone. The thinness of the squamous part o: 

 the temporal and the manner in which it is sutured to the parietal is also well displayed. 



